Redundant fans for cooling system

ABSTRACT

An apparatus includes a shared cooling device for cooling one or more systems or components, and a plurality of primary cooling pathways. Each of the primary cooling pathways includes a fan, and each fan is in fluid communication with the shared cooling device.

CROSS-REFERENCE TO RELATED APPLICATIONS

This patent application claims priority to and is a divisional patentapplication of U.S. patent application Ser. No. 15/709,507 filed on Sep.20, 2017 entitled “Redundant Fans for Cooling System”, which claimspriority to U.S. provisional patent application Ser. No. 62/399,097filed on Sep. 23, 2016 entitled “Improved Helicopter TransmissionSystem” and U.S. provisional patent application Ser. No. 62/423,371filed on Nov. 17, 2016 entitled “Improved Helicopter TransmissionSystem,” all of which are hereby incorporated by reference in theirentirety.

STATEMENT OF FEDERALLY FUNDED RESEARCH

Not applicable.

TECHNICAL FIELD OF THE INVENTION

The present invention relates in general to the field of rotorcraft, andmore particularly to methods and systems for cooling rotorcraft systems.

BACKGROUND OF THE INVENTION

Without limiting the scope of the invention, its background is describedin connection with rotorcraft drive systems.

Since their inception, rotorcraft and rotorcraft drive systems have beenimproved to reduce the possibility of failure during flight. Toward thatend, a number of modifications have been made to drive systems toimprove reliability. However, despite advances in materials and design,a number of failures continue to occur that affect rotorcraftperformance. One example of a problem with current rotorcraft drivesystems is that, in some instances, the failure of single drive systemcomponent leads to failure of the entire drive system. Another exampleis a loss of lubrication event that causes the loss of torquetransmission by drive system subcomponents such as gearboxes oraccessories connected to the main rotor gearbox.

More particularly, the failure of a single gearbox or shaft connected tothe main rotor gearbox can significantly impact operations. For example,if there is a loss of lubrication to a gearbox, the gearbox loses torquetransmission causing damage to upstream or downstream components. Thesame can occur when a shaft becomes unbalanced (or breaks), which candamage couplings, gearboxes and even the main rotor gearbox.Unfortunately, when a portion of a drive system experiences a failure orreduction in performance, the concomitant reduction in power leads tochallenges with flight performance.

Thus, a need remains for improving the overall safety and reliability ofrotorcraft drive systems that include the connections between theengines and the main rotor gearbox, reduction and accessory gearboxes,shafts, generators, oil pumps, and accessories connected to the mainrotor gearbox.

Existing methods and apparatuses for cooling systems such as a mainrotor gearbox and accessory gearboxes, and reduction gearboxes typicallydo not have a capacity for continued operation if components fail. If afan fails, for example, existing methods and apparatuses typically haveno ability to operate in the absence of the failed fan. Methods andapparatuses for providing redundancy for components of cooling systemsin rotorcraft are desirable.

SUMMARY OF THE INVENTION

In some embodiments of the disclosure, an apparatus includes a sharedcooling device for cooling one or more systems or components, and aplurality of primary cooling pathways. Each of the primary coolingpathways includes a fan, and each fan is in fluid communication with theshared cooling device. In some embodiments, the fan of each of theprimary cooling pathways is electrically powered independently ormechanically driven independently of a fan of any one of the otherprimary cooling pathways. In some embodiments, a shared connector is influid communication with the shared cooling device, wherein the sharedconnector is in fluid communication with each of the primary coolingpathways. In some embodiments, each of the primary cooling pathwaysfurther includes a transition duct in fluid communication with theshared cooling device, and the transition duct is in fluid communicationwith the fan of the primary cooling pathway. In some embodiments, eachof the primary cooling pathways further includes a transition connectorin fluid communication with the transition duct of the primary coolingpathway, and the transition connector is in fluid communication with thefan of the primary cooling pathway. In some embodiments, the apparatusfurther includes one or more secondary cooling pathways, wherein each ofthe one or more secondary cooling pathways includes: a conduit, whereinthe conduit is in fluid communication with the transition duct of one ofthe primary cooling pathways; and a distributed cooling device, whereinthe distributed cooling device is in fluid communication with theconduit. Each distributed cooling device can be operably coupled withthe one or more systems or components. In some embodiments, the one ormore systems or components include a main rotor gearbox, an accessorygearbox, one or more components driven by the accessory gearbox, areduction gearbox, a hydraulic system, a lubrication system, or atemperature control system. In some embodiments, the shared coolingdevice is operably coupled with one or more systems or components.

In some embodiments of the disclosure, a method of cooling one or moresystems or components includes providing a shared cooling device forcooling the one or more systems or components, and disposing a pluralityof primary cooling pathways by disposing a fan for each of the primarycooling pathways, wherein the fan is in fluid communication with theshared cooling device. In some embodiments, the fan of each of theprimary cooling pathways is electrically powered independently ormechanically driven independently of a fan of any one of the otherprimary cooling pathways. In some embodiments, a shared connector is influid communication with the shared cooling device, wherein the sharedconnector is in fluid communication with each of the primary coolingpathways. In some embodiments, the disposing of the plurality of primarycooling pathways further includes disposing a transition duct for eachof the primary cooling pathways by disposing the transition duct influid communication with the shared cooling device, and disposing thetransition duct in fluid communication with the fan of the primarycooling pathway. In some embodiments, the disposing the plurality ofprimary cooling pathways further includes disposing a transitionconnector for each of the primary cooling pathways by disposing thetransition connector in fluid communication with the transaction duct ofthe primary cooling pathway, and disposing the transition connector influid communication with the fan of the primary cooling pathway. In someembodiments, the method further disposes each of one or more secondarycooling pathway in fluid communication with one of the primary coolingpathways by disposing a conduit in fluid communication with thetransition duct of one of the primary cooling pathways, and disposing adistributed cooling device in fluid communication with the conduit. Insome embodiments, the method includes operably coupling each distributedcooling device with the one or more systems or components. In someembodiments, the one or more systems or components include a main rotorgearbox, an accessory gearbox, one or more components driven by theaccessory gearbox, a reduction gearbox, a hydraulic system, alubrication system, or a temperature control system. In someembodiments, the shared cooling device is operably coupled with one ormore systems or components.

In some embodiments of the disclosure, a rotorcraft includes a fuselage,one or more engines coupled to the fuselage, a shared cooling device forcooling an engine or a gearbox, wherein the shared cooling device iscoupled to the one or more engines, and a plurality of primary coolingpathways, wherein each of the primary cooling pathways comprises a fan,wherein each fan is in fluid communication with the shared coolingdevice. In some embodiments, the fan of each of the primary coolingpathways is electrically powered independently or mechanically drivenindependently of a fan of any one of the other primary cooling pathways.

In addition to the foregoing, various other method, system, andapparatus aspects are set forth in the teachings of the presentdisclosure, such as the claims, text, and drawings forming a part of thepresent disclosure.

The foregoing is a summary and thus contains, by necessity,simplifications, generalizations, and omissions of detail. Consequently,those skilled in the art will appreciate that this summary isillustrative only and is not intended to be in any way limiting. Thereaspects, features, and advantages of the devices, processes, and othersubject matter described herein will be become apparent in the teachingsset forth herein.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of the features and advantages of thepresent invention, reference is now made to the detailed description ofthe invention along with the accompanying figures, in which:

FIG. 1 shows a side view of a helicopter according to a particularembodiment of the present application;

FIG. 2 shows a partial cross-section, perspective view of a helicopteraccording to an embodiment of the present application;

FIG. 3A shows a perspective view of a cooling system;

FIG. 3B illustrates a transmission system and the interior view ofshared cooling device;

FIG. 4 shows a simplified diagram of a cooling apparatus;

FIG. 5 depicts a flowchart of a method of cooling one or more systems orcomponents;

FIG. 6 depicts a flowchart of another method of cooling one or moresystems or components;

FIG. 7 depicts a perspective view of a transition duct assembly;

FIG. 8 depicts a flowchart for a method of directing fluid flow in acooling apparatus;

FIG. 9 depicts a flowchart for another method of directing fluid flow ina cooling apparatus;

FIG. 10 depicts a perspective view of a redundant fan set in conjunctionwith a cooling apparatus;

FIG. 11 depicts a perspective view of a fan assembly;

FIG. 12 depicts a flowchart of a method of cooling one or more systemsor components;

FIG. 13 depicts a flowchart of another method of cooling one or moresystems or components;

FIG. 14 depicts a fan blade assembly mounted on a shaft; and

FIG. 15 depicts a flowchart of a method of cooling one or more systemsor components.

DETAILED DESCRIPTION OF THE INVENTION

Illustrative embodiments of the system of the present application aredescribed below. In the interest of clarity, not all features of anactual implementation are described in this specification. It will ofcourse be appreciated that in the development of any such actualembodiment, numerous implementation-specific decisions must be made toachieve the developer's specific goals, such as compliance withsystem-related and business-related constraints, which will vary fromone implementation to another. Moreover, it will be appreciated thatsuch a development effort might be complex and time-consuming but wouldnevertheless be a routine undertaking for those of ordinary skill in theart having the benefit of this disclosure.

In the specification, reference may be made to the spatial relationshipsbetween various components and to the spatial orientation of variousaspects of components as the devices are depicted in the attacheddrawings. However, as will be recognized by those skilled in the artafter a complete reading of the present application, the devices,members, apparatuses, etc. described herein may be positioned in anydesired orientation. Thus, the use of terms such as “above,” “below,”“upper,” “lower,” or other like terms to describe a spatial relationshipbetween various components or to describe the spatial orientation ofaspects of such components should be understood to describe a relativerelationship between the components or a spatial orientation of aspectsof such components, respectively, as the device described herein may beoriented in any desired direction.

The present invention addresses the problems with drive systems in usetoday that are known to lead to rotorcraft failure. More particularly,the drive system of the present invention was designed to overcome drivesystem failures by including one or more of the following designfeatures: (1) minimize the number of single path drive systemcomponents; (2) provide maximum system separation and redundancy; (3)minimize maintenance requirements and maintenance related incidents; (4)minimize the potential of loss of lubrication events; and/or (5)maximize main rotor gearbox loss of lubrication capability. Therotorcraft drive system described herein includes, e.g., dual enginereduction gearboxes completely isolated from the remainder of drivesystem via freewheeling clutches in the main rotor gearbox, dualaccessory gearboxes separate from the main rotor gearbox, and thedistribution of the gearbox driven accessories among the separatesystems, among other improvements.

The present invention was developed to address the failures common torotorcraft drive systems and is based on a completely new design andapplication of new technology to rotorcraft safety. More particularly,the new rotorcraft drive system is focused in an unparalleled manner onsafety and redundancy. The goal of safety drove the design anddevelopment of the unique layout and configuration of the rotorcraftdrive system described herein, which incorporates unique features andsystem separation that protects primary aircraft systems from the mostcommon drive system failures. The drive system has also been designed tomaximize the operational capability in the event of an uncommon failure,such as a loss of lubrication.

Moreover, the present inventors recognized that high-speed gearing andthe associated heat generation is always an area of concern for gearboxsurvivability. The ability to continue torque transmission, particularlyin a loss of lubrication scenario, is of great importance. For thisreason, the drive system described herein includes two separatereduction gearboxes (RGB's), each one connected to a separate engine andindependent from the Main Rotor Gearbox (MRGB). The reduction gearboxesare fully self-contained and separate from each other, each reducing theengine output speed from a high speed at or near turbine engine speed ofgreater than 10,000 RPM to a speed substantially lower than the highspeed, a low speed of less than about 6,000 RPM, prior to transmittingtorque to the MRGB. With this drive system arrangement high-speedgearing is contained in separate gearboxes, as such, the survivabilityof the total drive system is greatly enhanced, particularly in the eventof high-speed gear failure or loss of lubricant in an individual RGB.

With this arrangement, where high-speed gearing is contained in separategearboxes, the survivability of the total drive system is greatlyenhanced, particularly in the event of high speed gear failure or lossof lubricant in an individual RGB. Each reduction gearbox can bedisconnected from the MRGB by a clutch.

The Main Rotor Gearbox (MRGB) transmits torque from the ReductionGearboxes (RGB) to the main rotor mast, to the accessory gearboxes, tothe hydraulic pump and generator that is mounted to the MRGB, to thetail rotor drive shaft, and/or to the cooling fans.

The drive system and the associated cooling apparatus of the presentinvention can also take advantage of a number of additional featuresthat minimize the possibility of loss of lubricant, to maximize theoperational time if a loss of lubricant event does occur, and tomaximize the operational time if a fan in the cooling apparatus fails.The cooling apparatus can include redundant fans, a transition ductbetween a shared cooler and the redundant fans that enable one fan tocool an engine or gearbox if a fans fails, and fan blade assembliesmounted on drive shafts or gearshafts without the need for high-speedgrease-packed bearings. The drive system can also include one or more ofthe following: (1) the use of transfer tubes for cooler and filtermounting to eliminate the loss of lubricant in the event of loss ofattachment fastener torque; (2) using an oil cooler mounted directly tothe main rotor gearbox eliminating external hoses; (3) the use of alloil filter bowls are screw-on instead of held-on with small fastenerseliminating fastener failure issue from repeated removals; (4) theelimination of a high speed planetary and the heat generation associatedwith it during a loss of lubrication event; (5) the use of gear toothgeometry specifically designed to minimize sliding reducing heatgeneration at the teeth and the tendency to score during a loss oflubrication event; (6) the use of coarse pitch power gears withclearance or backlash allowing for the expansion during high heat lossof lubrication events; (7) the use of high hot hardness materialutilized for primary torque carrying components maximizing theircontinued operation during a loss of lubrication event; (8) the use ofring gear and case joint design to efficiently transmit heat away fromthe planetary gears in the event of a loss of lubrication event; and/or(9) the use of isotropic super finished gear teeth resulting in agreatly improved surface finish and maximizing the ability of thesegears to operate in a reduced lubrication environment.

FIG. 1 shows an aircraft 100 in accordance with a preferred embodimentof the present application. In the exemplary embodiment, aircraft 100 isa helicopter having a fuselage 102 and a rotor system 104 carriedthereon. A plurality of rotor blades 106 is operably associated with arotor system 104 for creating flight. A tail boom 108 is depicted thatfurther includes tail rotor 110.

For example, FIG. 2 shows a partial cross-section perspective view ofaircraft 100 that includes additional detail of the present invention.Aircraft 100 further includes a rotor mast 112, which is connected tothe main rotor gearbox 114 via a main rotor mast. The main rotor gearbox114 is connected to one or more accessory gear boxes 116 and one or morereduction gearboxes 216 a, 216 b. Each reduction gearbox 216 a, 216 b isconnected to one or more engines 120 a, 120 b, which are within anengine compartment 118. A tail rotor drive shaft 122 transmitsmechanical rotation to the tail rotor gear box 124, which is connectedvia tail rotor drive shaft 126 and intermediate gear box 128.

FIG. 3A shows a perspective view of an embodiment of the presentinvention, cooling apparatus 300. Cooling apparatus 300 includes ashared cooling device 305 through which air is drawn to cool a coolantsuch as oil. In FIG. 3A, shared cooling device 305 is illustrated asoperably coupled with main rotor gearbox 114 to cool oil circulatedthrough main rotor gearbox 114, but the skilled artisan will recognizethat cooling apparatus 300 may be used to cool other components with oilor other coolants. Shared cooling device 305 is exemplary; other typesof cooling mechanisms such as one or more coolers or heat exchangers maybe used for the same purpose. Shared cooling device 305 is in fluidcommunication through shared connector 310 with first transition duct320 and second transition duct 325.

In some embodiments, the first and second transition ducts 320 and 325partially extend into the shared connector 310 to provide systemredundancy in the event of a failed blower. Note that completeseparation of the flow paths is not required so long as there isadequate path separation to provide the required system redundancy. Inother embodiments, shared connector 310 includes partition 315 (notshown) that forms two channels within shared connector 310. One of thechannels is in fluid communication with first transition duct 320 andthe other channel is in fluid communication with second transition duct325. Shared connector 310 is illustrated here as articulated or actuatedto permit relative movement between shared cooling device 305 and thefirst transition duct 320 and second transition duct 325. Firsttransition duct 320 is in fluid communication with first transitionconnector 330 and second transition duct 325 is in fluid communicationwith second transition connector 335.

First transition connector 330 is in fluid communication with first fan340, which expels air through first exhaust port 341, and secondtransition connector 335 is in fluid communication with second fan 345,which expels air through second exhaust port 346. First fan 340 orsecond fan 345 may be a centrifugal fan, an axial-flow fan, a cross-flowfan, or another type of fan as convenient in various circumstances.First fan 340 and second fan 345 are operably independent of each other,including being electrically powered independently or mechanicallydriven independently of each other. First transition connector 330 andsecond transition connector 335 are illustrated here as articulated oractuated to permit relative movement between first fan 340 and firsttransition duct 320 on the one hand and, on the other hand, betweensecond fan 345 and second transition duct 325. The skilled artisan willrecognize that items in fluid communication may be in direct fluidcommunication, with the items in physical proximity, or in indirectfluid communication, with the items that are in fluid communicationseparated by other items. A transition duct, such as first transitionduct 320 and second transition duct 325, a transition connector, such asfirst transition connector 330 and second transition connector 335, or ashared connector, such as shared connector 310, may include at least aportion that is a rigid material, a flexible material, an articulatedportion, a flexible portion, or a combination thereof.

Continuing reference to FIG. 3A, first conduit 350 is in fluidcommunication with first transition duct 320 and second conduit 355 isin fluid communication with second transition duct 325. Firstdistributed cooling device 360 (e.g., heat exchanger) is in fluidcommunication with first conduit 350, and second distributed coolingdevice 365 (e.g., heat exchanger) is in fluid communication with secondconduit 355. First distributed cooling device 360 is a cooling systempowered by first accessory gearbox 116 a to cool a second hydraulicpower pack 370 (FIGS. 10-11). Second distributed cooling device 365 is acooling system powered by second accessory gearbox 116 b to cool a thirdhydraulic power pack 375 (FIGS. 10-11). Air is drawn through firstdistributed cooling device 360 to cool oil circulated through firstdistributed cooling device 360 by a hydraulic pump in second hydraulicpower pack 370 that is driven by the first accessory gearbox 116 a.Likewise, air is drawn through second distributed cooling device 365 tocool oil circulated through second distributed cooling device 365 by ahydraulic pump in third hydraulic power pack 375 that is driven by thesecond accessory gearbox 116 b. First distributed cooling device 360 andsecond distributed cooling device 365 are exemplary; other types ofcooling mechanisms such as one or more coolers or heat exchangers may beused for the same purpose. A conduit, such as first conduit 350 andsecond conduit 355, may include at least a portion that is a rigidmaterial, a flexible material, an articulated portion, a flexibleportion, or a combination thereof.

First fan 340, first transition connector 330, and first transition duct320 are included in a first primary cooling pathway and second fan 345,second transition connector 335, and second transition duct 325 areincluded in a second primary cooling pathway. First fan 340 draws airthrough the first primary cooling pathway from shared cooling device305, which cools oil circulated through shared cooling device 305 frommain rotor gearbox 114 and expels the heated air through first exhaustport 341. Second fan 345 draws air through the second primary coolingpathway from shared cooling device 305, which cools oil circulatedthrough shared cooling device 305 from main rotor gearbox 114 and expelsthe heated air through second exhaust port 346. Cooling apparatus 300 isillustrated as having two primary cooling pathways from shared coolingdevice 305, but the skilled artisan will recognize that coolingapparatus 300 may have two or more such primary cooling pathways. Theskilled artisan will also recognize that where there are more than twoprimary cooling pathways, shared connector 310 will have more than twochannels, each of which is in fluid communication with a distincttransition duct. The skilled artisan will further recognize that wherethere are more than two primary cooling pathways, each cooling pathwayincludes a fan, and all of the fans are operably independent of eachother, including being electrically powered independently ormechanically driven independently of each other. A transition connector,such as first transition connector 330 and second transition connector335, may include at least a portion that is a rigid material, a flexiblematerial, an articulated portion, a flexible portion, or a combinationthereof. The skilled artisan will recognize that a cooling pathway, suchas the first and second primary cooling pathways herein, may have moreor fewer items than those illustrated or discussed herein.

First conduit 350 and first distributed cooling device 360 are includedin a secondary cooling pathway and second conduit 355 and seconddistributed cooling device 365 are included in a secondary coolingpathway. First distributed cooling device 360 cools oil from secondhydraulic power pack 370 that is circulated by a hydraulic pump insecond hydraulic power pack 370 driven by the first accessory gearbox116 a. Likewise, second distributed cooling device 365 cools oil fromthird hydraulic power pack 375 that is circulated by a hydraulic pump inthird hydraulic power pack 375 driven by the second accessory gearbox116 b. First fan 340 draws air from first distributed cooling device 360through first conduit 350 and first transition duct 320, and it expelsthe air through first exhaust port 341. Second fan 345 draws air fromsecond distributed cooling device 365 through second conduit 355 andsecond transition duct 325, and it expels the air through second exhaustport 346.

In an embodiment of cooling apparatus 300 with more than two primarycooling pathways, there is a single shared cooling device 305, a singleshared connector 310, and three or more primary cooling pathways, eachwith a transition duct corresponding to first transition duct 320 andsecond transition duct 325, a transition connector corresponding tofirst transition connector 330 and second transition connector 335, anda fan corresponding to first fan 340 and second fan 345. In an aspect ofcooling apparatus 300, there may be a secondary cooling pathwayincluding a conduit corresponding to first conduit 350 and secondconduit 355 and a distributed cooling device corresponding to firstdistributed cooling device 360 and second distributed cooling device365. The skilled artisan will recognize that a cooling pathway, such asthe first and second secondary cooling pathways herein, may have more orfewer items than those illustrated or discussed herein.

FIG. 3B illustrates a transmission system and an interior view of sharedcooling device 305, which includes one or more exemplary cores, e.g.,main rotor gearbox core 306, left-hand reduction gearbox core 307,right-hand gearbox core 308, and hydraulic systems core 309. Each ofthese cores in this multicore shared cooling device 305 is in fluidcommunication with shared connector 310 (not shown), and each of thecores is oriented to partition 315 such that airflow through coolingapparatus 300 can be maintained for cooling all of the systems orcomponents served by these cores—main rotor gearbox 114, reductiongearboxes, one or more hydraulic systems, one or more lubricationsystems, or one or more thermal control systems (such as other coolingsystems or heating systems)—when both first fan 340 and second fan 345are functioning and when only one fan, either first fan 340 or secondfan 345, is operating, e.g., in the event of a fan failure. With thecores oriented perpendicular or orthogonal to the partition 315, airdrawn through either the first primary cooling pathway or the secondprimary cooling pathway, in the event of a fan failure, or both coolingpathways in normal operations, flows through all of the cores, mainrotor gearbox core 306, left-hand reduction gearbox core 307, right-handgearbox core 308, and hydraulic systems core 309. Although theorientation of the cores is shown to be generally perpendicular ororthogonal to the partition 315, the skilled artisan will recognize thatthe cores and inlets to the cores may be made in other shapes andorientations such that the airflow across the cores can be other thanperpendicular, e.g., at a 15, 20, 30, 45, 60, 80, or 85 degree anglewhile still providing airflow across the cores. Each core of the one ormore cores included in shared cooling device 305 can be oversized tohave sufficient cooling capacity to cool all of the systems orcomponents coupled to it to maximize operational time in the event of afan failure. As previously discussed, partition 315 is not required ifthe transition ducts partially extend into the shared connector 310 toprovide sufficient separation such that system redundancy is provided inthe event of a failed blower. Note that complete separation of the flowpaths is not required as long as there is adequate path separation toprovide the required system redundancy. In this case, the cores can begenerally oriented to the transition ducts extending into the sharedconnector 310. When partition 315 is used, it can be fixed, articulatedor actuated. To provide improved redundancy, partition 315 can bearticulated or actuated to increase airflow across a greater area ofshared cooling device 305 by moving to one side on shared connector 310,allowing air drawn through the primary cooling path of the operating fanto draw air over most or all of each of the cores, e.g., main rotorgearbox core 306, left-hand reduction gearbox core 307, right-handgearbox core 308, and hydraulic systems core 309. Hydraulic systems core309 cools a first hydraulic power pack (not shown).

FIG. 4 depicts a simplified diagram of cooling apparatus 300. FIG. 4shows main rotor gearbox 114, shared cooling device 305, sharedconnector 310, partition 315 (optional), first channel 316, secondchannel 317, first transition duct 320, second transition duct 325,first transition connector 330, second transition connector 335, firstfan 340, first exhaust port 341, second fan 345, second exhaust port346, first conduit 350, second conduit 355, first distributed coolingdevice 360, second distributed cooling device 365, first accessorygearbox 116 a, and second accessory gearbox 116 b. Arrows depictairflows through the primary and secondary cooling pathways from theshared cooling device 305 and from the first distributed cooling device360 and second distributed cooling device 365 through first fan 340 andsecond fan 345 and out through first exhaust port 341 and second exhaustport 346. In some embodiments, partition 315 is eliminated and thepartition functionality is provided by the length in which the ducts 320and 325 extend forward into connector 310. In some other embodiments,partition 315 is fixed in place. In yet some other embodiments,partition 315 can be articulated or actuated to move to one side or theother of shared connector 310 in the event of a fan failure, allowingair drawn through the primary cooling path of the operating fan to drawair over most or all of each of the cores included in shared coolingdevice 305. In FIG. 4, partition 315 is depicted as a solid line in theposition in which air is drawn through both the first and second primarycooling pathways and as dotted lines in the positions in which partition315 is moved to one side or the other of shared connector 310.

Here, cooling apparatus 300 is shown operably coupled with main rotorgearbox 114, first accessory gearbox 116 a and second accessory gearbox116 b to power shared cooling device 305, first distributed coolingdevice 360 and second distributed cooling device 365, respectively. Theskilled artisan will recognize that cooling apparatus 300 may beoperably coupled to cool other systems or components than thosespecifically described herein, such as the first accessory gearbox 116a, second accessory gearbox 116 b, first reduction gearbox 216 a, secondreduction gearbox 216 b, other hydraulic systems, one or morelubrication systems, or one or more thermal control systems. The skilledartisan will also recognize that cooling apparatus 300 may be used withother cooling mechanisms besides coolers such as shared cooling device305, first distributed cooling device 360, and second distributedcooling device 365.

FIG. 5 depicts a flowchart of a method 500 of cooling one or moresystems or components, illustrating an embodiment of the presentinvention. Method 500 includes block 505, providing a shared coolingdevice 305 for cooling one or more systems or components, such as themain rotor gearbox 114, the accessory gearboxes 116 a, 116 b, one ormore components driven by the accessory gearboxes 116 a, 116 b,reduction gearboxes 216 a, 216 b, one or more hydraulic systems (e.g.,first hydraulic power pack), one or more lubrication systems, or one ormore thermal control systems, and further includes block 510, disposingeach of a plurality of primary cooling pathways in fluid communicationwith the shared cooling device 305 by disposing a transition duct, suchas first transition duct 320 or second transition duct 325, in fluidcommunication with the shared cooling device 305 and disposing a fan,such as first fan 340 or second fan 345, in fluid communication with thetransition duct.

FIG. 6 depicts a flowchart of a method 600 of cooling a component,illustrating another embodiment of the present invention. Method 600includes block 605, providing a shared cooling device 305 for coolingone or more systems or components, such as the main rotor gearbox 114,the accessory gearboxes 116 a, 116 b, one or more components driven bythe accessory gearboxes 116 a, 116 b, the reduction gearboxes 216 a, 216b, one or more hydraulic systems (e.g., first hydraulic power pack), oneor more lubrication systems, or one or more thermal control systems.Method 600 further includes block 610, disposing a first transition duct320 in fluid communication with the shared cooling device 305. Method600 further includes block 615, disposing a first fan 340 in fluidcommunication with the first transition duct 320. Method 600 furtherincludes block 620 disposing a first conduit 350 in fluid communicationwith the first transition duct 320. Method 600 further includes block625, disposing a first distributed cooling device 360 in fluidcommunication with the first conduit 350. Method 600 further includesblock 630, disposing a second transition duct 325 in fluid communicationwith the shared cooling device 305. Method 600 further includes block635, disposing a second fan 345 in fluid communication with the secondtransition duct 325. Method 600 further includes block 640, disposing asecond conduit 355 in fluid communication with the second transitionduct 325. Method 600 further includes block 645, disposing a seconddistributed cooling device 365 in fluid communication with the secondconduit 355.

The skilled artisan will recognize that cooling apparatus 300 andmethods 500 and 600 of cooling a system or component providesafety-enhancing redundant cooling for aircraft systems or components byproviding more than one cooling pathway for the system or component tobe cooled, permitting continued operations if a cooling pathway becomesinoperative.

FIG. 7 shows a perspective view of an embodiment of the presentinvention, transition duct assembly 700. Transition duct assembly 700includes a shared connector 310. Within shared connector 310, partition315 (optional) forms first channel 316 and second channel 317 withinshared connector 310. Transition duct assembly 700 is exemplary of anytype of mechanical connection or connections that places ducts and fansin fluid communication. In some embodiments, partition 315 is eliminatedand the partition functionality is provided by the lengths by which theducts 320 and 325 extend forward into connector 315. In some otherembodiments, partition 315 is fixed in place. In yet some otherembodiments, partition 315 can be articulated or actuated to increaseairflow across a greater area of shared cooling device 305. In anembodiment in which transition duct assembly 700 is part of coolingapparatus 300, in normal operations with both first fan 340 and secondfan 345 operating, first channel 316 is in fluid communication withfirst transition duct 320, and second channel 317 is in fluidcommunication with second transition duct 325. First transitionconnector 330 is in fluid communication with first transition duct 320and second transition connector 335 is in fluid communication withsecond transition duct 325. First conduit 350 is in fluid communicationwith first transition duct 320 and second conduit 355 is in fluidcommunication with second transition duct 325. When partition 315 ismoved to one side or the other of shared connector 310, one of firstchannel 316 or second channel 317 is closed off and the remaining openchannel is usable through which to draw air through either firsttransition duct 320 or second transition duct 325 to cool the systems orcomponents cooled by shared cooling device 305.

FIG. 8 depicts a flowchart of a method 800 for directing fluid flow in acooling apparatus such as cooling apparatus 300, illustrating anembodiment of the present invention. Method 800 includes block 805,providing a shared connector 310; optional block 810, forming a one ormore channels, e.g. first channel 316 and second channel 317, within theshared connector 310; and block 815, providing each of a plurality ofprimary cooling pathways for cooling one or more systems or components,such as the main rotor gearbox 114, the accessory gearboxes 116 a, 116b, one or more components driven by the accessory gearboxes 116 a, 116b, the reduction gearboxes 216 a, 216 b, one or more hydraulic systems,one or more lubrication systems, or one or more thermal control systems,wherein each of the primary cooling pathways is in fluid communicationwith the shared connector 310 by disposing a transition duct, e.g.,first transition duct 320 or second transition duct 325, operablyconfigured to be placed in fluid communication with one of the pluralityof channels, e.g., first channel 316 or second channel 317 (or theshared connector 310); and disposing a transition connector, e.g., firsttransition connector 330 or second transition connector 335, in fluidcommunication with the transition duct, e.g., first transition duct 320or second transition duct 325.

FIG. 9 depicts a flowchart of a method 900 for directing fluid flow in acooling apparatus such as cooling apparatus 300, illustrating anembodiment of the present invention. Method 900 includes block 905,providing a shared connector 310; block 910, forming two channels, firstchannel 316 and second channel 317, within the shared connector; block915, disposing a first primary cooling pathway for cooling one or moresystems or components, such as the main rotor gearbox 114, the accessorygearboxes 116 a, 116 b, one or more components driven by the accessorygearboxes 116 a, 116 b, the reduction gearboxes 216 a, 216 b, one ormore hydraulic systems, one or more lubrication systems, or one or morethermal control systems, wherein the first primary cooling pathway is influid communication with the shared connector 310, further includingdisposing a first transition duct 320 in fluid communication with afirst channel 316 of the two channels, first channel 316 and secondchannel 317, and disposing a first transition connector 330 in fluidcommunication with the first transition duct 320; and block 920,disposing a second primary cooling pathway for cooling one or moresystems or components, such as the main rotor gearbox 114, the accessorygearboxes 116 a, 116 b, one or more components driven by the accessorygearboxes 116 a, 116 b, the reduction gearboxes 216 a, 216 b, or one ormore hydraulic systems, one or more lubrication systems, or one or morethermal control systems, wherein the second primary cooling pathway isin fluid communication with the shared connector 310, further includingdisposing a second transition duct 325 in fluid communication with asecond channel 317 of the two channels, first channel 316 and secondchannel 317, and disposing a second transition connector 335 in fluidcommunication with the second transition duct 325.

The skilled artisan will recognize that transition duct assembly 700 andmethods 800 and 900 of cooling one or more systems or components providesafety-enhancing redundant cooling for aircraft systems or components byproviding more than one cooling pathway for the system or component tobe cooled, permitting continued operations if a cooling pathway becomesinoperative.

FIG. 10 shows a perspective view of an embodiment of the presentinvention, redundant fan set 1000, in conjunction with cooling apparatus300. Redundant fan set 1000 includes two fan assemblies, the first fanassembly 1005 including first fan 340 and first exhaust port 341, andthe second fan assembly 1010 including second fan 345 and second exhaustport 346. First fan 340 expels air through first exhaust port 341, andsecond fan 345 expels air through second exhaust port 346. First fan 340and second fan 345 are operably independent of each other, includingbeing electrically powered independently or mechanically drivenindependently of each other. If either fan fails, the other fan willcontinue to operate despite the failure. First fan 340 and second fan345 each independently have the capacity to move air through a coolingapparatus such that the systems or components to be cooled can be cooledby either first fan 340 operating by itself or second fan 345 operatingby itself. FIG. 10 also shows main rotor gearbox 114, first accessorygearbox 116 a, second accessory gearbox 116 b, second hydraulic powerpack 370, third hydraulic power pack 375 of aircraft 100 as examples ofcomponents that require cooling.

FIG. 11 depicts a perspective view of first fan assembly 1005, includingfirst fan 340, first exhaust port 341, and first fan blade assembly1105. FIG. 11 also depicts first distributed cooling device 360, firstaccessory gearbox 116 a and second hydraulic power pack 370.

FIG. 12 depicts a flowchart of a method 1200 of cooling one or moresystems or components, illustrating an embodiment of the presentinvention. Method 1200 includes block 1205, providing a shared coolingdevice 305 for cooling one or more systems or components, such as themain rotor gearbox 114, accessory gearboxes 116 a, 116 b, one or morecomponents driven by the accessory gearboxes 116 a, 116 b, reductiongearboxes 216 a, 216 b, or one or more hydraulic systems, one or morelubrication systems, or one or more thermal control systems, and alsoincludes block 1210, disposing a plurality of primary cooling pathwaysby disposing a fan for each of the primary cooling pathways, wherein thefan, e.g., first fan 340 or second fan 345, is in fluid communicationwith the shared cooling device 305.

FIG. 13 depicts a flowchart of a method 1300 of cooling one or moresystems or components, illustrating another embodiment of the presentinvention. Method 1300 includes block 1305, providing a shared coolingdevice 305 for cooling one or more systems or components, such as themain rotor gearbox 114, accessory gearboxes 116 a, 116 b, one or morecomponents driven by the accessory gearboxes 116 a, 116 b, reductiongearboxes 216 a, 216 b, or one or more hydraulic systems, one or morelubrication systems, or one or more thermal control systems. Method 1300further includes block 1310, disposing a first fan 340 in fluidcommunication with the shared cooling device. Method 1300 also includesblock 1315, disposing a second fan 345 in fluid communication with theshared cooling device, wherein the first fan 340 and the second fan 345are electrically powered independently or mechanically drivenindependently of each other.

The skilled artisan will recognize that redundant fan set 1000 andmethods 1200 and 1300 provide safety-enhancing redundant cooling foraircraft systems or components by providing more than one fan for thesystem or component to be cooled, permitting continued operations if afan becomes inoperative.

FIG. 14 depicts an embodiment of the present invention, a fan bladeassembly mounted on a shaft. The skilled artisan will recognize that ashaft on which a fan blade assembly is mounted may be a drive shaft or agearshaft. Shown here is first fan blade assembly 1105 of first fan 340mounted on first gearshaft 1115. First gearshaft 1115 protrudes from andis operably coupled to first accessory gearbox 116 a to be turned byfirst accessory gearbox 116 a. First accessory gearbox 116 a is a devicefor transmitting energy by rotating first gearshaft 1115. When firstaccessory gearbox 116 a turns the first gearshaft 1115, first fan bladeassembly 1105 turns with first gearshaft 1115. Thus, the operation offirst accessory gearbox 116 a turns first fan blade assembly 1105 offirst fan 340, which draws air through first distributed cooling device360, first conduit 350, first transition duct 320, and first transitionconnector 330 (not shown here; see FIGS. 3A and 4), to cool the secondhydraulic power pack 370 and components driven by the first accessorygearbox 116 a. Not shown here is a similar arrangement for second fan345, in which second fan assembly of second fan 345 is mounted on asecond gearshaft that protrudes from and is operably coupled to secondaccessory gearbox 116 b to be turned by second accessory gearbox 116 b,so that when second accessory gearbox 116 b turns the second gearshaft,second fan 345 draws air to cool the third hydraulic power pack 375 andcomponents driven by the second accessory gearbox 116 b. Using agearshaft in this manner drives each fan independently because each fanblade assembly is a on a separate gearshaft of a separate accessorygearbox. If one accessory gearbox fails and the associated fan bladeassembly stops turning, another accessory gearbox, absent an independentfailure, will continue to operate and will continue to draw air to coolthe system or component being cooled by the cooling apparatus 300. Theskilled artisan will recognize that a fan blade assembly may include animpeller, a rotor, or another assembly of blades associated with a fanor a blower generally.

FIG. 15 depicts a flowchart of a method 1500, a method for cooling a oneor more systems or components, illustrating another embodiment of thepresent invention. Method 1500 includes block 1505, providing one ormore fans, e.g., first fan 340 or second fan 345, wherein each of theone or more fans includes a fan blade assembly, e.g. first fan bladeassembly 1105. Method 1500 further includes block 1510, operablycoupling each of one or more shafts, e.g., first gearshaft 1115, to anengine or a gearbox, such as the engines 120 a, 120 b, the accessorygearboxes 116 a, 116 b, or the reduction gearboxes 216 a, 216 b, andwherein each fan blade assembly, e.g. first fan blade assembly 1105, ofthe one or more fans, e.g., first fan 340 or second fan 345, is disposedon one of the shafts e.g., first gearshaft 1115. The skilled artisanwill recognize that each of a plurality of fan blade assemblies can bemounted on a shaft such as a gearshaft to provide as many shaft-mountedfan blade assemblies as may be needed for a given application.

The skilled artisan will recognize that method 1500 and mounting a fanblade assembly, such as first fan blade assembly 1105, directly on agearshaft, such as first gearshaft 1115, eliminate the need for bearingsto support the first fan blade assembly 1105, further eliminating theneed for maintenance and replacement of bearings and enhancing safety.

It will be understood that particular embodiments described herein areshown by way of illustration and not as limitations of the invention.The principal features of this invention can be employed in variousembodiments without departing from the scope of the invention. Thoseskilled in the art will recognize, or be able to ascertain using no morethan routine experimentation, numerous equivalents to the specificprocedures described herein. Such equivalents are considered to bewithin the scope of this invention and are covered by the claims.

All publications and patent applications mentioned in the specificationare indicative of the level of skill of those skilled in the art towhich this invention pertains. All publications and patent applicationsare herein incorporated by reference to the same extent as if eachindividual publication or patent application was specifically andindividually indicated to be incorporated by reference.

The use of the word “a” or “an” when used in conjunction with the term“comprising” in the claims and/or the specification may mean “one,” butit is also consistent with the meaning of “one or more,” “at least one,”and “one or more than one.” The use of the term “or” in the claims isused to mean “and/or” unless explicitly indicated to refer toalternatives only or the alternatives are mutually exclusive, althoughthe disclosure supports a definition that refers to only alternativesand “and/or.” Throughout this application, the term “about” is used toindicate that a value includes the inherent variation of error for thedevice, the method being employed to determine the value, or thevariation that exists among the study subjects.

As used in this specification and claim(s), the words “comprising” (andany form of comprising, such as “comprise” and “comprises”), “having”(and any form of having, such as “have” and “has”), “including” (and anyform of including, such as “includes” and “include”) or “containing”(and any form of containing, such as “contains” and “contain”) areinclusive or open-ended and do not exclude additional, unrecitedelements or method steps. In embodiments of any of the compositions andmethods provided herein, “comprising” may be replaced with “consistingessentially of” or “consisting of.” As used herein, the phrase“consisting essentially of” requires the specified integer(s) or stepsas well as those that do not materially affect the character or functionof the claimed invention. As used herein, the term “consisting” is usedto indicate the presence of the recited integer (e.g., a feature, anelement, a characteristic, a property, a method/process step, or alimitation) or group of integers (e.g., feature(s), element(s),characteristic(s), property(ies), method/process(s) steps, orlimitation(s)) only.

The term “or combinations thereof” as used herein refers to allpermutations and combinations of the listed items preceding the term.For example, “A, B, C, or combinations thereof” is intended to includeat least one of: A, B, C, AB, AC, BC, or ABC, and if order is importantin a particular context, also BA, CA, CB, CBA, BCA, ACB, BAC, or CAB.Continuing with this example, expressly included are combinations thatcontain repeats of one or more item or term, such as BB, AAA, AB, BBC,AAABCCCC, CBBAAA, CABABB, and so forth. The skilled artisan willunderstand that typically there is no limit on the number of items orterms in any combination, unless otherwise apparent from the context.

As used herein, words of approximation such as, without limitation,“about,” “substantial” or “substantially” refers to a condition thatwhen so modified is understood to not necessarily be absolute or perfectbut would be considered close enough to those of ordinary skill in theart to warrant designating the condition as being present. The extent towhich the description may vary will depend on how great a change can beinstituted and still have one of ordinary skill in the art recognize themodified feature as still having the required characteristics andcapabilities of the unmodified feature. In general, but subject to thepreceding discussion, a numerical value herein that is modified by aword of approximation such as “about” may vary from the stated value byat least ±1, 2, 3, 4, 5, 6, 7, 10, 12 or 15%.

All of the devices and/or methods disclosed and claimed herein can bemade and executed without undue experimentation in light of the presentdisclosure. While the devices and/or methods of this invention have beendescribed in terms of particular embodiments, it will be apparent tothose of skill in the art that variations may be applied to thecompositions and/or methods and in the steps or in the sequence of stepsof the method described herein without departing from the concept,spirit and scope of the invention. All such similar substitutes andmodifications apparent to those skilled in the art are deemed to bewithin the spirit, scope, and concept of the invention as defined by theappended claims.

Furthermore, no limitations are intended to the details of constructionor design herein shown, other than as described in the claims below. Itis therefore evident that the particular embodiments disclosed above maybe altered or modified and all such variations are considered within thescope and spirit of the disclosure. Accordingly, the protection soughtherein is as set forth in the claims below.

Modifications, additions, or omissions may be made to the systems andapparatuses described herein without departing from the scope of theinvention. The components of the systems and apparatuses may beintegrated or separated. Moreover, the operations of the systems andapparatuses may be performed by more, fewer, or other components. Themethods may include more, fewer, or other steps. Additionally, steps maybe performed in any suitable order.

To aid the Patent Office, and any readers of any patent issued on thisapplication in interpreting the claims appended hereto, applicants wishto note that they do not intend any of the appended claims to invokeparagraph 6 of 35 U.S.C. § 112 as it exists on the date of filing hereofunless the words “means for” or “step for” are explicitly used in theparticular claim.

What is claimed is:
 1. A rotorcraft, comprising: a fuselage; one or moreengines or a gearbox coupled to the fuselage; a shared cooling devicecoupled to the one or more engines or the gearbox; a shared connector influid communication with the shared cooling device; two or more ofprimary cooling pathways, wherein each of the primary cooling pathwayscomprises a fan in fluid communication the shared connector via atransition duct, and wherein each fan is configured to draw air from theshared cooling device; and one or more secondary cooling pathways,wherein each of the one or more secondary cooling pathways comprisesdistributed cooling device in fluid communication with the transitionduct of one of the primary cooling pathways via a conduit, andoptionally or preferably wherein each distributed cooling device isoperably coupled with one or more systems or components.
 2. Therotorcraft of claim 1, wherein the fan of each of the primary coolingpathways is electrically powered independently or mechanically drivenindependently of a fan of any one of the other primary cooling pathways.3. The rotorcraft of claim 1, wherein the gearbox comprises a main rotorgearbox, an accessory gearbox, one or more components driven by theaccessory gearbox, or a reduction gearbox.
 4. The rotorcraft of claim 1,wherein the one or more systems or components comprise the main rotorgearbox, an accessory gearbox, one or more components driven by theaccessory gearbox, a reduction gearbox, a hydraulic system, alubrication system, or a temperature control system.
 5. The rotorcraftof claim 1, further comprising one or more partitions within the sharedconnector, wherein each partition forms a channel within the sharedconnector for two of the transition ducts.
 6. The rotorcraft of claim 5,wherein the one or more partitions are articulated or actuated to moveto one side or the other of shared connector.
 7. The rotorcraft of claim1, wherein the two or more transition ducts extend into the sharedconnector forming a channel for each transition duct.
 8. The rotorcraftof claim 1, further comprising a transition connector coupled betweeneach fan and the respective transition duct.
 9. The rotorcraft of claim1, further comprising an exhaust port coupled to each fan.
 10. Arotorcraft comprising: a fuselage; one or more engines coupled to thefuselage; a main rotor gearbox coupled to the one or more engines; ashared cooling device coupled to the main rotor gearbox; a sharedconnector coupled to the shared cooling device; a first transition ductcoupled to the shared connector; a second transition duct coupled toshared connector; a first fan coupled to the first transition duct; asecond fan coupled to the second transition duct; a first conduitcoupled to the first transition duct; a second conduit coupled to thesecond transition duct; a first distributed cooling device coupled tothe first conduit; a second distributed cooling device coupled to thesecond conduit; a first system or component coupled to the firstdistributed cooling device; and a second systems or components coupledto the second distributed cooling device.
 11. The rotorcraft of claim10, wherein the first fan is electrically powered independently ormechanically driven independently of the second fan.
 12. The rotorcraftof claim 10, wherein the first and second systems or components comprisean accessory gearbox, one or more components driven by the accessorygearbox, a reduction gearbox, a hydraulic system, a lubrication system,or a temperature control system.
 13. The rotorcraft of claim 10, furthercomprising a partition within the shared connector that forms a firstchannel coupled to the first transition duct and a second channelcoupled to the second transition duct.
 14. The rotorcraft of claim 13,wherein the partition is articulated or actuated to move to one side orthe other side of the shared connector.
 15. The rotorcraft of claim 10,wherein: the first transition duct extends into the shared connectorforming a first channel; and the second transition duct extends into theshared connector forming a second channel.
 16. The rotorcraft of claim10, further comprising: a first transition connector coupled between thefirst fan and the first transition duct; and a second transitionconnector coupled between the second fan and the second transition duct.17. The rotorcraft of claim 10, further comprising: a first exhaust portcoupled to the first fan; and a second exhaust port coupled to thesecond fan.